The Sun and its planetary system formed from heterogeneous debris1-11 of asupernova (SN) that exploded 5 billion years ago12,13. Meteorites and planets recorded this as decay products of short-lived nuclides and linked variations in elemental and isotopic abundances. Cores of the inner planets grew in the central iron-rich region of the SN debris, and the Sun formed on the collapsed SN core. See Figs. 1-5.

Diffusion enriches lighter elements and the lighter isotopes of each element at the solar surface14-16. When corrected for mass fractionation, the most abundant nuclide that accreted on the Sun was shown17 to be 56Fe, the decay product of doubly-magic 56Ni; the next most abundant nuclide is the doubly-magic 16O. These nuclides were abundantly produced18 in SN 1987A. The most abundant elements - Fe, Ni, O, Si, S, Mg, and Ca - are the seven, even-Z elements that Harkins19 found to comprise 99% of ordinary meteorites. The least abundant elements - Li, Be and B - have loosely bound nucleons, confirming a link19 between abundances and nuclear structure hidden beneath the Sunís H-rich surface, with one conspicuous and important exception - an excess of protons. See Figs. 6-8.

3-D plots20-22 of energy vs. charge density vs. mass or atomic numbers for the ground-state nuclides reveal a cradle, shaped like the trough made by cupping the hands together, that contains all nuclear matter in the universe (Figs. 9-12).

The Sunís radiant energy and protons in the solar wind (SW)
come from the collapsed supernova core, a neutron star (NS), on which the Sun
formed. The cradle (Figs. 9-12) indicates that the energy of each neutron in
the Sunís central NS exceeds that of a free neutron by
@ 10-22 MeV (Figs. 13-15) Solar luminosity and the flux of solar-wind
protons are generated by a series of reactions (Fig. 16): a) escape of neutrons
from the central NS, b) decay of free neutrons or their capture by other nuclides,
c) fusion and upward migration of H+ through material that accreted
on the NS, and d) escape of H+ in the SW. An example might be:

a) The escape of neutrons from the NS, <1n>
Ė> 1n + 10-22 MeV

b) The decay of free neutrons,
1n Ė> 1H+ + e- + nanti
+ 0.78 MeV

c) Fusion of hydrogen, 4 1H+
+ 2 e- Ė> 4He++ + 2
n + 26.73 MeV

d) Some H+ reaches the surface and departs in
the solar wind

Reactions like a) and b) produce part of the Sunís radiant energy and perhaps the luminosity of isolated neutron stars25. Note that reaction a) alone may release more energy per nucleon than is released by the sum of reactions b) and c), the decay or capture of neutrons plus H-fusion. The well-established Solar Neutrino Puzzle26 confirms that reaction c) generates only part of the Sunís total luminosity. Most 1H+ from b) is consumed by H-fusion, but the anomalous abundance of H (See Fig. 8) shows that 1H+ also leaks from the interior, selectively carrying lighter nuclides to the solar surface (See Fig. 6) before departing in the solar wind at an emission rate of about 2.7 x 10431H/yr. Homochirality in living creatures26was likely initiated by circularly polarized light (CPL) from the Sunís early NS. Their fate and climate changes of planets27 may depend on the half-life of this massive nucleus at the Sunís core.

Acknowledgements The support of the Foundation for Chemical Research, Inc. is gratefully acknowledged. This conclusion to our 40-year effort to understand the origin of the Solar System and its elements would not have been possible without moral support and encouragement from the late Professors Glenn T. Seaborg and Raymond L. Bislinghoff.

Figure Captions (Click on Figure titles to reach the Figures)

Figure 1. The solar system formed out of the debris of a single supernova (SN) and the Sun formed on its collapsed core1-11. This explains the data in Figs. 2-5.

Figure 2. Combined 244Pu/136Xe and 238,235U/206,207Pb age dating shows that the supernova (SN) exploded about 5 billion years ago12.

Figure 3.26Al/26Mg age dating shows that condensation began almost immediately, trapping high values of 26Al/27Al in SiC and in graphite grains of meteorites within 1-10 million years (0.001-0.010 billion years) of the supernova13. Grains that started to condense earlier grew larger, like fallout particles from nuclear weapons. They also trapped elements before complete mixing of isotopes made in various SN layers. These isotopic anomalies are illustrated in Figure 5.

Figure 4. Primordial He and Ne from the outer SN layers were trapped in carbon-rich meteorite grains with excess 136Xe (on the right). Isotopically "normal" Xe came from the interior of the star where fusion had destroyed light elements like He and Ne (on the left). The r-process made excess 136Xe in the outer stellar layers where He and Ne remained. Shown here are data for mineral separates of the Allende meteorite. The linkage of primordial He and Ne with excess 136Xe is observed in all types of meteorites4 and in the He-rich atmosphere of Jupiter10.

Figure 5. The isotopic anomaly patterns of numerous elements show excesses and deficits of the same isotope in different meteorite grains5,9,11. These elements display "mirror-image" isotopic anomaly patterns because elements of normal isotopic composition are mixtures of the isotopically anomalous components made in different SN layers. This illustrates the isotopic anomaly patterns observed in three elements with seven stable isotopes, Ba, Nd and Sm.

Figure 7.After correcting for the mass-fractionation shown in Figure 6, the most abundant elements in the bulk Sun are Fe, Ni, O, Si, S, Mg and Ca14-17. In 1917 Harkins19 reported that these same, even-Z elements comprise 99% of meteorites.

Figure 8. Fractionation-corrected solar abundances are linked to nuclear stability17, as suggested by Harkins19 in 1917, except for a large excess of H leaking from the Sunís interior. This figure is published in Ref. 17 and 20.

Figure 9. This plot of mass per nucleon, M/A, vs. charge per nucleon, Z/A, for all stable and long-lived nuclides shows that 1H has both the highest potential energy (M/A) and the highest charge density (Z/A). By contrast, 56Fe has the lowest potential energy (M/A) and an ordinary value of Z/A (charge density). First published in a report20 to FCR, Inc., this figure is reproduced in Ref. 17.

Figure 10. A 3-D plot of ground state nuclides shows the nuclear energy surface that defines the cradle of matter in the universe. Shown here are potential energy, M/A, vs. charge density, Z/A, vs. mass number, A, for all data available in the sixth edition of Nuclear Wallet Cards23. Parabolas of isobars showing mass per nucleon and b-decay energies per nucleon arerepresent by slices through the cradle at constant A. First published here, this figure is reproduced in Ref. 21.

Figure 11. A 3-D plot of ground state nuclides shows the "cradle" as a function of atomic number, Z. The isotopes of each element, represented by slices through the cradle at constant Z, define mass parabolas that are related by the capture or emission of neutrons. First published here, this figure is reproduced in Ref. 21.

Figure 12. Least-square lines fit to
the parabolas at each value of A (Fig. 10) are used to estimate potential energy
per nucleon for isobars, from Z/A = 0 (Z,A = 0,A) to Z/A = 1 (Z,A = A,A). The
data in Fig. 11 can also be used to estimate the potential energy of isotopes
from Z/A = 1 (Z,A = Z,Z) to Z/A @ 0 (Z,A = Z,infinity),
a very massive nucleus composed completely of neutrons, except for the Z protons.

Figure 13. The "cradle" from Figure 12 predicts values of M/A when the charge density is zero, Z/A = 0, for odd values of A = 1-263. First published here, this figure is reproduced in Ref. 22.

Figure 14. The potential energy of particles in a neutron star can be estimated by extrapolating values of M/A at Z/A = 0 from Figure 12 to a neutron star at 1/A
@ 0. The "best fit" line through all values of A yields an intercept at 1/A = 0 suggesting that these particles will have
@ 10 MeV more energy that the free neutron. First published here, this figure is reproduced in Ref. 22.

Figure 15. The potential energy of particles in a neutron star can be estimated by considering only A > 150 and extrapolating values of M/A at Z/A = 0 from Figure 12 to a neutron star at 1/A
@ 0. The intercept of this "best fit" line at 1/A = 0 suggests that these particles will have
@ 22 MeV more energy that the free neutron. First published here, this figure is reproduced in Ref. 22.

Figure 16. Nuclear reactions that generate the Sunís luminosity and the excess 1H shown in Figure 8. The energy generated by reactions 1a, 1b and 1c can be represented by vertical transmissions between the lines in Figure 15. The emission and decay of neutrons may contribute to the luminosity of isolated neutron stars24. The flux of solar neutrinos25 confirms that reactions 1c and 2c, H-fusion, generate only part of the Sunís total radiant energy.

19. W. D. Harkins, "The evolution of the elements and the stability of complex atoms. I. A new periodic system which shows a relation between the abundance of the elements and the structure of the nuclei of atoms," J. Am. Chem. Soc. 39, 856-879 (1917).